Self-priming centrifugal pump



Jan. 19, 1954 H. TROEGER' ETAL SELF-PRIMING CENTRIFUGAL. PUMP FiledSept. 28, 1949 1; 75 l2 1 1 l 8 I l I 7048 769 3 78 25 no 64 i 54 2 P aa 46 I4 aw, 43

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ll Q INVENTORS HENRY TROEGER 5 0 ROBE/P7" M. FLANAGAN ATTORNE PatentedJan. 19,1954

SELF-PRIMING CENTRIFUGAL PUMP Henry Troeger, Ramsey, and Robert M.Flanagan,

Morris Plains, N. J., assignors to Bendix Aviation Corporation,Teterboro, N. J.,'a corporation of Delaware Application September 28,1949, Serial No. 118,204

' 6 Claims.

The present invention relates to pumps and more particularly to those ofthe centrifugal self priming type. V

The invention consists in the combination with an engine driven pump ofa reciprocating type of priming pump which is mounted so as to beoperative before. the engine driven pump begins to handle fluid, andinoperative after the engine driven pump has begun to pump fluid insufficient quantity. 7

A centrifugal liquid pump consists essentially of a rotary impeller, orrotor having passages extending from the center to the peripherythereof. The pump operates by the inertia or centrifugal throw of theliquid in these passages. A centrifugal pump will only function when ithas liquid in its rotor. Therefore, a centrifugal pump will not start inoperation if it must lift the liquid to be pumped, and will stopoperation or become air bound if it does not have a continuous supply ofliquid.

' It is therefore one of the objects of the present invention to providea novel type of self priming centrifugal liquid pump which will startoperating immediately and wherein the priming means will beautomatically rendered inoperative once the centrifugal pump beginspumping liquid.

Another object of the invention is to provide a pump of the aboveindicated nature wherein the moving parts are a minimum.

Still another object of the invention is to provide a self primingcentrifugal liquid pump free from expensive and complicated gearing. v

Still another object of the invention is to provide a self primingcentrifugal liquid pump wherein a positive displacement pump is used forpriming an impeller, and pressure from the impeller then renders thepriming means inoperative once the centrifugal pump is in operation.

Another object of the invention is to provide centrifugal pumpingapparatus of the type indicated which is of very rugged construction andupon which upkeep will be reduced to a minimum.

Another object of the invention is to provide a pumping unit embodyingmeans for initially priming the pump, and for priming the pump at anytime it loses its suction, and to provide means of said type which arerelatively simple inconstruction and require no delicate adjustments.

Another object of the invention is to provide an eificient and compactarrangement of the above indicated nature.

The foregoing and other objects and advantages will appear more fullyhereinafter from a consideration of the detailed description whichfollows, taken together with the accompanying drawing wherein oneembodiment of the invention is illustrated by way of example. It is tobe expressly understood, however, that the drawing is for the purposesof illustration only and is not to be construed as defining the limitsof the invention.

Referring now to the drawings, wherein like reference charactersdesignate like parts,

Figure 1 is an elevation in section of the pumping unit attached to thedriving motor.

Figure 2 is an end view of Figure 1.

Figure 3 is a portion of a sectional view taken along the line 33 ofFigure 2.

Referring now to the drawing and more particularly to Figure l, a pumpIE! has a casing II including a cylindrical portion l2 perpendicularthereto. A pipe threaded inlet l4 communicates with a chamber l 6 whichis blocked off by a check valve 18. The check valve I8 is of a typecommonly employed in the art, and will permit flow only in onedirection, herein indicated by the arrow A, and then only uponovercoming the force of a spring 23 which tends to bias the valvetowards closed position. 7

The chamber l6 thereupon communicates through a passage 22 with theinterior of a chamber 24 which houses a cylindrical sleeve bearing 25 inwhich is rotatably mounted the shaft 26 of the rotor or impeller 23. Therotor or impeller 28 contains one or more internal passages 36 whichcommunicate with the hollow 32 of the shaft 26 which is a usual featureof similar devices, except that the shaft 26 contains an exterior groove34 eccentrically out about its outside surface 36 for reasonshereinafter explained. A slot 38 in the hub 40 of the shaft 26 engagesin some suitable manner the driving shaft 62 which in turn passesthrough the inner race of a ball bearing 44 to engage the power shaft 46of the driving motor 48. Annular seals 56 and 52 disposed about theshaft 42 tend to prevent any leakage which in any event would becollected in chamber 54! and conducted out through the drain 56.

The cylindrical portion [2 of the casing III has an interior bore 58accessible by means of the threaded cap 60. The bore 53 extends into thechamber 2 but is sealed from direct communication therewith by sleevebearing 25 and hollow shaft 26. Bore 58 houses a piston 62 which duringthe priming operation abuts the eccentric groove 34 of the shaft 26. Aspring 64 anchored at one end to a stationary sleeve 66 and at the otherend to a flange 68 on the piston 62 tends to keep the piston 62positioned against the eccentric groove 34.

A passageway 18 leads from the inlet Hi to a port H formed in the sleeve66 and which communicates the passageway III with an intake chamber 12about and above the piston 62 and a valve '14 normally maintained incontact with sleeve 65 by means of spring I5 forms one wall of saidintake chamber.

A second passageway 16 leads from the priming pump discharge chamber 11to the chamber it on the downstream side of Referring now to Figures 1and 3 combined, the openings 38 in the impeller 28 lead into an annularchamber 18, one portion thereof (Fi ure 3) leading by means of passage80 to a pressure throttling valve 82 of a type well known in the art,and hence to the pump outlet 84, and another portion thereofcommunicating by means of passageway 86 to the groove 34 at theunderside of the piston 62.

Having thus described the invention, it will now be apparent to thoseskilled in the art that when the inlet 14 is connected to a source ofliquid and the pump I8 is driven by the motor 48, the eccentric groove34 in the turnin shaft 25, abutting against the piston 62, will causesaid piston to travel up and down within the sleeve 66 thereby creatinga suction at each stroke in the intake chamber 12. Fluid will inconsequence be drawn from the inlet [4, up the passageway 10, throughthe port H which is uncovered by the downstroke of the piston 62 andinto the chamber 12. Upon the upstroke of the piston 62 the port 1| willbe closed by the piston $2 and fluid will be trapped in the chamber '52,and the force of spring I5 will be overcome thereby lifting the valve 14and permitting the fluid to pass into the chamber H whereupon it will bedriven down the passageway 16 into the chamber H5 in the downstream sideof the check valve l8, and therefrom into the hollow 32 of the shaft 26to provide priming for the impeller 28.

The radial passages 30 thereupon pass the liquid centrifugally into theannular chamber 18 from whence it passes through the passageway 89 andthe pressure throttling valve 82, to the outlet 84.

When sufficient priming liquid has thus been provided to the chamber l6and pumped out by the impeller 28, a reduced pressure is necessarilyproduced in the chamber 16 and in the hollow 32 of the shaft '26,whereupon the pressure against the valve 18 on the upstream side willovercome the spring 20 to open the valve, and permit the liquid to enterthe hollow 32 of the shaft 26 directly from the inlet M.

The centrifugal impeller 28 having thus commenced pumping at rapidlyincreasing capacity, the manner in which the priming means are suspendedis as follows:

The passageway 86 connects the annular centrifugal pump chamber 18 tothe groove 34 at the underside of the piston 62, thereby pressure fluidis transmitted to the underside of piston 82. As the impeller 28 takesover and begins to pump liquid at pressure the piston =62 will be heldfrom its eccentric groove 34 against the force of the spring 64 by thefluid pressure from the impeller 28 and will not operate.

In the event that the fluid pressure created by the impeller 28 drops toa value insufficient to overcome the force of the spring 5-4, the piston62 will be urged against the eccentric groove 34 and the priming processwill begin again.

The pressure throttling valve '82 is set to a the check valve I8.

desired value so that the fluid delivery pressure of the pump cannotbecome excessive and is thereby regulated.

It is to be noted that the structure and the arrangement of the deviceprovides a self primer for a centrifugal liquid pump which is drivenfrom the same shaft as is the centrifugal pump, Without complicated andexpensive gearing and with a minimum of moving parts, and which operatesonly until positive pressure is built up by the centrifugal pump, atwhich time the primer is made automatically inactive, thereby leavingthe impeller 28 as the only moving part.

There are thus provided self-contained means for priming a centrifugalpump which are of economical and rugged construction, compact inarrangement, and yet positive and reliable in operation.

Although only one embodiment and one application of the invention hasbeen illustrated and described, other changes and 'modifications in theform and relative arrangement of parts which will be apparent to thoseskilled in the art may be made without departing from the spirit andscope of the invention.

What is claimed 1. in a centrifugalpump driven by a motor, thecombination comprising a casing including an inlet and an outlet, athrough bore and an impeller chamber in said casing in axial alignmentwith said inlet, a check valve in said bore restricting the flow fromsaid inlet to a predetermined pressure, a bearing in said bore, animpeller in said impeller chamber having a hollow shaft rotatabiymounted in said bearing, said hollow shaft having an open endcommunicating with said inlet downstream of said check valve, theinterior of said impeller communicating with r the interior of saidhollow shaft, the exterior of said hollow shaft being grooved to form aneccentric cam surface, a driving shaft attached to said impeller andadapted to be driven by said motor, a second bore in said casingperpendicular to said first bore and extending through said bearing andisolated from said through bore by said bearing and hollow shaft, afirst sleeve concentric within said second bore, a movable piston withinsaid sleeve, spring means anchored to said sleeve normally urging saidpiston against said cam surface, a liquid intake chamber in said secondbore above said piston, a passage in said casing from said inlet to saidintake chamber including a port in said sleeve, a discharge chamber insaid second bore, a valve controlling communication between said intakeand discharge chambers, a passage in said casing from said dischargechamber to said through bore downstream of said check valve and upstreamof the open end of said hollow shaft, a pressure throttling valve ofpredetermined setting intercommunicating said impeller chamber and saidoutlet, passageway means from said impeller chamber opening to saidsecond bore below said piston to conduct fluid pressure to the undersideof said piston to overcome said spring means and render said pistoninoperative thereby preventing priming liquid flow from said inlet tothe downstream side of said check valve upon said impeller operating toopen said check valve and pump liquid directly from said inlet.

2. In a self-priming motor driven centrifugal pump, the combinationcomprising a casing including an inlet and an outlet, a first bore andan impeller chamber in said casing in axial align ment with said inlet,a bearing in said first bore, an impeller in saidimpeller chamber having-a hollow shaft communicating with the interior of said impeller androtatably mounted in said bearing, said hollow shaft having an open endadjacent to and in communication with said inlet, a check valve ofpredetermined setting in said inlet upstream of the open end of saidhollow shaft, a second bore in said casing perpendicular to said firstbore and extending through said bearing, said first and second boresbeing isolated from each other by said bearing and hollow shaft, theexterior surface of said hollow shaft being grooved toform a camsurface, a piston within said second bore normally contacting said camsurface, an intake chamber in said second bore above said piston, afirst passage in said casing from said inlet upstream of said checkvalve to said intake chamber, a discharge chamber in said second bore, avalve in said second bore controlling communication between g saidintake and discharge chambers, a second passage in said casing from saiddischarge chamber to the downstream side of said check valve andupstream of the open end of said hollow shaft, a pressure regulatingvalve intercommunicating'said impeller chamber and said outlet,passageway means from said impeller chamber to the underside of saidpiston, a motor, a driving shaft connecting said motor to said impellerto rotate said impeller and hollow shaft thereby 3,,

actuating said piston to pass liquid from said inlet through said firstand second passages to the end of said hollow shaft bypassing said checkvalve to effect said impeller to pump said liquid to said outlet andbeneath said piston, to overcome said predetermined setting and opensaid check valve and raise said piston above and out of contact withsaid cam surface.

3. In a self-priming centrifugal pump, the combination comprising acasing having an inlet, a check valve in said inlet, a bore in saidcasing communicating with said inlet, a hollow shaft rotatably supportedin said bore and having an open end disposed adjacent to and incommunication with the downstream side of said check valve, an impelleron the opposite end of said hollow shaft, the open end of said hollowshaft forming the inlet of said impeller, a chamher in said casing aboutsaid impeller, a cam surface on said hollow shaft, a cylinder in saidcasing having a piston mounted for reciprocation therein, an intakechamber in said cylinder above said piston, a discharge chamber in saidcylinder, valve means controlling communication between said intake anddischarge chambers, a first passageway in said casing from said inletupstream of said check valve to said intake chamber, a second passagewayfrom said discharge chamber to the downstream side of said check valveand upstream the open end of said hollow shaft, spring means holdingsaid piston in contact with said cam surface on said hollow shaft foroperating said piston to draw liquid from said inlet through said firstpassageway into said intake chamber and to force the liquid from saidintake chamber through said valve means, discharge chamber and secondpassageway to the open end of said hollow shaft to prime saidcentrifugal pump.

4. In a self-priming centrifugal pump, the combination comprising acasing having an inlet and. an outlet, a bore in said casing downstreamof said inlet, a hollow shaft rotatably mounted in said bore and havingan open end adjacent to and communicating with said inlet, an impelleron the other end of said hollow shaft, the interior of said hollow shaftcommunicating with the interior of said impeller, an output chamber insaid casing surrounding said impeller and communicating with saidoutlet, said impeller being constructed and arranged to provide a flowof fluid from said inlet through said hollow shaft and impeller to saidoutput chamber upon rotation of said impeller, a check valve ofpredetermined setting mounted in said inlet upstream of the open end ofsaid hollow shaft to control the flow of liquid through said inlet tothe open end of said hollow shaft, said check valve closing said inletwhen said impeller is stationary,

by-pass passageway means in said casing from said inlet upstream of saidcheck valve to downstream of said check valve for lay-passing said checkvalve and to deliver liquid to the open end of said hollow shaft fromsaid inlet upstream of said check valve, valve means controlling flowthrough said by-pass passageway means, said hollow shaft having anexterior groove forming a cam surface, pumping means including a pistonnormally engaging said cam surface and actuated thereby for pumpingliquid from said inlet to the open end of said hollow shaft through saidby-pass passageway means and valve means, and other passageway meansbetween the output chamber and the underside of said piston, and turningmeans attached to said impeller and operative to rotate said impellerand hollow shaft whereby said pumping means delivers liquid from saidinlet through said by-pass passageway means and valve means to the openend of said hollow shaft to prime said impeller to overcome saidpredetermined setting of said check valve and open the same to permitliquid to flow from said inlet through said hollow shaft to saidimpeller, and said other passageway means serving to deliver liquidpressure from said output chamber to the underside of said piston todisengage said piston from said cam surface.

5. In a self-priming liquid centrifugal pump, the combination comprisinga casing having an inlet and an outlet, a check valve in said inlet, abore in said casing downstream of said inlet,

a hollow shaft rotatably mounted in said bore,

said hollow shaft having an open end communicating with said inletthrough said bore, an

' impeller on the other end of said hollow shaft having its interiorcommunicating with the interior of said hollow shaft, an impellerchamber in said casing disposed about said impeller and communicatingwith said outlet, said impeller operative upon rotation to provide aflow of liquid under pressure from said inlet through said check valve,hollow shaft, impeller and impeller chamber to said outlet, a camsurface formed on said hollow shaft, priming means including a cylinderin said casing, liquid passageway means in said casing connecting saidcylinder to the upstream and downstream sides respectively of said checkvalve, a piston in said cylinder operatively engaged with said camsurface, valve means in said cylinder operated by said piston andcontrolling flow through said liquid passageway means, said pistonoperative to pump liquid through said passageway means from said inletto the open end of said hollow shaft bypassing said check valve, drivingmeans operatively connected to said impeller for rotating said impellerand hollow shaft, and means for disengaging said piston from said camsurface comprising a passageway between said impeller 6. In aself-priming centrifugal pump, the

combination comprising a casing having an inlet and an outlet, a bore insaid casing downstream of said inlet, a hollow shaft rotatably mountedin said bore and having an open end adjacent to and communicating withsaid inlet, an impeller on the other end of said hollow shaft, theinterior of said hollow shaft communicating with the interior of saidimpeller, an output chamber in said casing surrounding said impeller andcommunicating with said outlet, said impeller being constructed andarranged to provide a flow of fluid from said inlet through said hollowshaft and impeller to said output chamber upon rotation of saidimpeller, a check valve of predetermined setting mounted in said inletupstream of the open end of said hollow shaft to control the flow ofliquid through said inlet to the open end of said hollow shaft, saidcheck valve closing said inlet when said impeller is stationary, acylinder in said casing, a piston mounted for reciprocation in saidcylinder, an intake chamber in said cylinder above said piston, a firstpassageway from said inlet upstream of said check valve to said intakechamber, a discharge chamber in said cylinder, valve means controllingflow between said intake and discharge chambers, a second passagewayfrom said 8 1 discharge chamber to the open end of said hol low shaft, acam surface on said hollow shaft, spring means urging said piston intocontact with said cam surface whereby rotation of said hollow shaftreciprocates said piston to pump priming liquid from said inlet throughsaid first passageway, intake chamber, valve means, discharge chamberand second passageway to the open end of said hollow shaft, and impellersustained liquid pressure means operative on said piston tointermittently cut out said piston upon said priming liquid reaching asufiicient pressure.

HENRY TROEGER. ROBERT M. FLANAGAN.

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